« previous next »
Pages: [1]   Go Down

Author Topic: Sync'd carbs, now bike won't idle  (Read 1172 times)

0 Members and 1 Guest are viewing this topic.

Offline B.O.X.N.I.F.E.

  • The Stumped
  • Expert
  • ****
  • Posts: 1,137
Sync'd carbs, now bike won't idle
« on: June 23, 2011, 01:32:12 AM »
Let me say first these carbs were screwed with by someone who's idea of rebuilding was replacing perfectly good jets with keyster kits slathered in LITHIUM GREASE???

I rebuilt them correctly and installed them on the bike. It idled but when I hooked up my carbtune the sync was awful, wildly different vacuum in each carb. A buddy held them at 3k while I sync'd them but now the idler screw won't touch the tab on the linkage.

Is there a mechanical explanation in the linkage the PO may have messed with that I didn't catch? Or is my sync job the likely culprit?
Logged
1974 CB550

32 days and 5,536 miles on a CB550...

http://kerncountykid.blogspot.com/

and a couple years later, 38 days and 9,102 miles...

Forever West

... and all of it in a 4 mintue video

<a href="Not a valid vimeo URL">WWYY?[/url]

Offline WarwickE36

  • Expert
  • ****
  • Posts: 761
Re: Sync'd carbs, now bike won't idle
« Reply #1 on: June 23, 2011, 06:26:50 AM »
Basically what the last guy said.  You need to make sure you down keep adjusting counterclockwise, if you keep going in that direction you will eventually run out of room. In other words when you finish syncing your master idle screw wont be touching anymore.  Its happened to me before... turn all of the adjusters in a few turns (make sure to do them all equally) and re-sync .. I also dont think 3k is a good place to sync at try 1,500Rpms... once you are close to a good sync idle down to 1k and make sure it will go down this low.
Logged
" Why does anyone get offended by what someone does to their own bike? I dont get it. "

You made me think about it after I cheered knowing someone else would like to know what these control freaks are up to.
 Every time any owner strips whatever precious Honda part the horrified purists parts go up in value. That's not the part that bothers them.
 What bothers them is they sat up late at night, their breast full of wonder and estrogen, unable to sleep, dreaming about their lovely darling and all her glory... and next thing you know someone else doesn't share their emotional deluge and their reaction is they must spread their mind museum as far as they possibly can, taking over as much of the real world as possible.

Drink fast, drive slow, but ride it like you stole it

1974 Cb550 with style
2004 SV650s

Offline flybox1

  • My wife thinks I'm a
  • Really Old Timer ...
  • *******
  • Posts: 14,301
Re: Sync'd carbs, now bike won't idle
« Reply #2 on: June 23, 2011, 06:57:10 AM »
did you do a bench sync first?
that will get all your slides close, and then only small adjustments are needed during the vac sync to make big changes in vacuum.
once you get your bike idling, do your sync at 1500rpms.
as you make your adjustments, the idle will change, adjust it back to 1500 and continue. repeat.
Logged
'78 750K (F3 engine) PD42b's, Modified airbox w/K&N  filter, 40/110 jets, 1 needle shim, IMS@ 1 turn out. Kerker + Cone 18" QuietCore

Past Bikes
1974 550K0 (stock), 1973 CB350F (stock), 1983 Yamaha XS400K (POS)
77/78 cool 2 member #3
"Knowledge without mileage equals bullsh!t" - Henry Rollins

"This is my CB. There are many like it, but this one is mine…"

Offline fmctm1sw

  • Old Timer
  • ******
  • Posts: 3,042
Re: Sync'd carbs, now bike won't idle
« Reply #3 on: June 23, 2011, 06:47:14 PM »
Quote from: flybox1 on June 23, 2011, 06:57:10 AM
did you do a bench sync first?

+1.  I always looked through the front and only left a sliver of an opening below the slides on each of them to get started.. 
Logged
Quote from: 754
Dude is that a tire ? or an O-ring..??

Quote from: inkscars
This is not a pod thread
This is not a #$%* on my vacuum gauges thread
This is a help or GTFO thread.

1973 CB350F
1973 CB350G
1975 CB550K
1983 GL650I
1973 CB750K3 (http://forums.sohc4.net/index.php?topic=92888.0)
1984 Kawasaki KLT-250 (AKA 3 wheeler of death)
1994 Honda TRX300
1999 Honda TRX250
Pages: [1]   Go Up
« previous next »